A composite index; socioeconomic deprivation and coverage of reproductive and maternal health interventions

Abstract Objective To examine inequalities in the coverage of reproductive and maternal health interventions in low- and middle-income countries and territories using a composite index of socioeconomic deprivation status. Methods We obtained data on education and living standards from national household surveys conducted between 2015 and 2019 to calculate socioeconomic deprivation status. We assessed the coverage of reproductive and maternal health interventions, using three indicators: (i) demand for family planning satisfied with modern methods; (ii) women who received antenatal care in at least four visits; and (iii) the presence of a skilled attendant at delivery. Absolute and relative inequalities were evaluated both directly and using the slope index of inequality and the concentration index. Findings In the 73 countries and territories with available data, the median proportions of deprivation were 41% in the low-income category, 11% in the lower-middle-income category and less than 1% in the upper-middle-income category. The coverage analysis, conducted for 48 countries with sufficient data, showed consistently lower median coverage among deprived households across all health indicators. The coverage of skilled attendant at delivery showed the largest inequalities, where coverage among the socioeconomically deprived was substantially lower in almost all countries. Antenatal care visits and demand for family planning satisfied with modern methods also showed significant disparities, favouring the less deprived population. Conclusion The findings highlight persistent disparities in the coverage of reproductive and maternal health interventions, requiring efforts to reduce those disparities and improve coverage, particularly for skilled attendant at delivery.


Introduction
Eliminating poverty in all its forms is the first of the 17 sustainable development goals (SDGs). 1 People living in conditions of poverty are likely to have fewer opportunities for health care, thus experiencing more adverse health outcomes and a higher risk of preventable and premature death. 2 Furthermore, inequities in the coverage of reproductive, maternal and child health interventions correlate strongly with disparities in maternal and child mortality. 3,4Hence, addressing these inequities is important not only for reducing maternal and child mortality rates, but also for the advancement of SDG 3, which aims to ensure healthy lives and promote well-being for all. 1 Monitoring and analysing inequalities across various dimensions, such as subnational regions and poverty levels is essential for tracking progress towards the SDGs, aimed at leaving no one behind.Understanding these disparities is key to identifying strategies and policies that can break vicious cycles of ill-health and poverty. 5pplying an equity lens is particularly important in lowand middle-income countries, which are home to the largest share and number of people living in conditions of poverty. 6ost of these countries rely on national household surveys as their primary source of information for reproductive, maternal and child health.Traditionally, socioeconomic inequalities have been assessed in these surveys by using a combination of assets (such as mobile phones, refrigerators and bicycles), basic services and household materials to generate a score to rank households' wealth. 7This score, or wealth index, is often divided into five equally sized groups and presented as wealth quintiles.][10] The aim of the index is to provide a relative wealth distribution for the country at the time of the survey.Hence, its design affects the suitability for cross-country comparisons and broader comparisons over time.The index tends to favour urban populations, a bias partly influenced by better infrastructure and higher asset ownership in urban areas.Furthermore, the index, based on a single dimension of socioeconomic position, presents a different picture from consumption or expenditure.Recently, we proposed a multidimensional measure of socioeconomic deprivation, integrating education and material living standards, inspired by the United Nations (UN) Multidimensional Poverty Index. 6,8he new measure benefits from being an absolute measure of deprivation with fixed cut-offs, unlike the wealth index score, which changes from country to country, and even from survey to survey within the same country.As with the wealth index, the new socioeconomic deprivation status can be calculated using data from national health surveys.
Using this new measure of socioeconomic deprivation status, we conducted a comprehensive analysis of the distribution of socioeconomic deprivation across 73 low-and middleincome countries and territories.We subsequently describe and compare reproductive and maternal health inequalities Inequalities in health indicators by socioeconomic deprivation status Leonardo Z Ferreira et al.
for those countries with significant levels of deprivation, using the measure of socioeconomic deprivation status.The findings establish a baseline for monitoring progress in increasing coverage and reducing inequalities in essential health indicators.

Methods
To calculate the composite index of socioeconomic deprivation status, we obtained data from household surveys conducted by the Demographic and Health Surveys 11 and the Multiple Indicator Cluster Survey 12 programmes.These surveys are designed to be na-tionally representative by employing a multistage sampling framework, that often uses census tracts as the primary sampling unit.In April 2022, we selected the most recent surveys conducted after 2015 that had available data for the calculation of the socioeconomic deprivation status measure from all low-and middle-income countries and territories.
We calculated the socioeconomic deprivation status by using eight indicators across the two dimensions, education and living standards (Table 1).The educational indicators cover school attendance of school-aged children, and years of schooling for household members older than 10 years.The living standards indicators cover the type of fuel used for cooking, access to improved sanitation facilities, a safe source of drinking water and electricity, as well as assets ownership and adequate housing materials.Each indicator is coded as 1 for deprived households and 0 for non-deprived households.We then combined these indicators to generate a composite deprivation score, whereby each dimension accounts for 50% of the total weight, with each indicator having equal weights within each dimension.The composite score ranges from 0 to 1, with higher values indicating more severe status of socioeconomic deprivation of a household and its members.Based on the original cut-offs, the score intervals were broken down into three groups: not deprived (score ranging from 0 to 0.25); vulnerable (score ranging from above 0.25 to 0.50); and deprived (score above 0.50).In this study, the deprived group combines the deprived and extremely deprived categories from the original socioeconomic deprivation status, 6 as the sample size for the extremely deprived group was too small (below 25 households) for meaningful analyses.
To examine how the level of socioeconomic deprivation status related to coverage of reproductive and maternal health interventions, we selected commonly used key indicators to monitor these interventions.Furthermore, these indicators have large sample sizes in the surveys used.We generated estimates for three indicators covering the reproductive, pregnancy and birth stages: (i) demand for family planning satisfied with modern methods; (ii) women who received antenatal care in at least four visits; and (iii) the presence of a skilled attendant at delivery.Detailed definitions of all indicators can be found in Table 2.
We disaggregated coverage estimates for these indicators by the socioeconomic deprivation status.We visually evaluated equity patterns according to the inverse equity hypothesis. 13This hypothesis proposes that health coverage first increases in wealthier populations.As a result, absolute health inequalities are expected to widen initially, only diminishing when these interventions eventually reach the more deprived groups.Hence, upon introducing new health interventions, top inequality patterns often emerge, where the most privileged group (that is, the non-deprived group) benefits, leaving other groups behind.As the interventions reach more people, bottom inequality patterns usually arise when the most deprived group considerably lags behind. 13When the gaps between the groups are of similar magnitude, it is referred to as linear inequality.We assessed absolute and relative health inequalities using the slope index of inequality and the concentration index, respectively.Both measures range from −100 to +100, where negative values indicate higher coverage for the most disadvantaged, positive values indicate higher coverage for the households with less deprivation, and zero indicates absence of inequality. 14e restricted the coverage analyses to countries with sufficient sample sizes (at least 25 households) for the socioeconomic deprivation status.Results are presented by country or territory, and grouped according to the World Bank's country income level classification 15 for the year the survey was completed.We conducted all analyses using Stata version 17 (StataCorp.LP, College Station, United States of America), accounting for sampling weights and the clustered design of the surveys.Ethical clearance was obtained by the United States Agency for International Development and the United Nations Children's Fund, which funded the data collection.

Results
A total of 73 countries and territories were eligible for the study, comprising 22 low-income, 26 lower-middleincome and 25 upper-middle-income countries and territories (Table 3).The distribution of the socioeconomic deprivation status in each country or territory is presented in Fig. 1.In half (25) of the low-and lower-middleincome countries and territories, over a quarter of the population was classified as deprived.Among low-income countries, the median proportion of deprivation was 41%, with Chad recording the highest weighted proportion at 74%.Among lower-middle-income countries and territories, the median proportion of deprivation was 11%, ranging from a weighted proportion of 0% in Armenia and Kyrgyzstan to 40% in Mauritania.For upper-middle-income In our coverage analysis of reproductive and maternal health interventions, we excluded 25 surveys due to insufficient sample sizes in the deprived group, analysing in total 48 countries.Fig. 2 presents the estimated distribution of the three indicators of reproductive and maternal health for each group of the socioeconomic deprivation status.For all three indicators, the median coverage was consistently lower among individuals in deprived households, regardless of the country income classification.Low-income countries showed a linear equity pattern in the demand for family planning satisfied with modern methods across the different socioeconomic deprivation status groups, showing a median gap of 13 percentage points between deprived and non-deprived groups (Fig. 2).These differences were smaller in lower-middle and upper-middleincome countries, although coverage was still lower among the most deprived individuals.As for indicators on women who received antenatal care in at least four visits, and had a skilled attendant at delivery, the median gaps between groups were much larger than for demand for family planning satisfied with modern methods (Fig. 2).While the median coverage for skilled attendant at delivery for the non-deprived surpassed 90% in all country income categories, the coverage remained below 50% among the deprived households in lowand lower-middle-income countries and was slightly above 60% for uppermiddle-income countries.
Sufficient data on demand for family planning satisfied with modern methods were available for 46 countries.Coverage of demand for family planning satisfied with modern methods by country is presented in Fig. 3. Half (nine) of the low-income countries exhibit top inequality and linear inequality patterns, while the remaining half present small differences between the socioeconomic deprivation status groups.We observed more consistent bottom inequality patterns in lower-middle-income countries, where coverage among the deprived is half that of the non-deprived and vulnerable, as seen in Cameroon and Nigeria.Across all 45 countries, the slope index of inequality shows gaps that exceed 20 percentage points in 16 countries, and four countries show higher demand for family planning satisfied with modern methods coverage among the deprived (available in online repository). 16e observed a similar pattern driven by top and linear inequality for women who received antenatal care in at least four visits in low-income countries (Fig. 4).A linear pattern is also evident in lower-middle-and uppermiddle-income countries, with few bottom inequality cases such as Indonesia, Iraq, Paraguay and Peru.The magnitude of the differences is much greater for women who received antenatal care in at least four visits in comparison to the demand for family planning satisfied with modern methods.The slope index of inequality shows that gaps above 60 percentage points exist in Angola, Lao People's Democratic Republic, Nigeria and Pakistan (available in online repository). 16Only six countries (Gambia, Kiribati, Peru, Sao Tome and Principe, Zambia and Zimbabwe) showed no inequalities between socioeconomic deprivation status groups.
Fig. 5 shows that in most countries, individuals in the non-deprived group have considerably higher coverage of skilled attendants at delivery.

Discussion
Here we provide a large-scale empirical analysis of reproductive and maternal health inequalities using a novel, absolute and internationally comparable composite index of socioeconomic deprivation status, which is based on household survey data.The results demonstrate a clear contrast in health indicator coverage between deprived or vulnerable individuals and those in more privileged socioeconomic positions.Indeed, findings highlight that reproductive and maternal health cover-age among socioeconomically deprived individuals is substantially lower than coverage among privileged individuals in almost all low-and middle-income countries and across the three indicators studied.
Our results are consistent with previous research, which shows that individuals in higher socioeconomic positions are more likely to have a skilled attendant at delivery compared to those facing socioeconomic disadvantages. 17,18ur results indicate that in nearly all countries, least deprived groups are closest to achieving universal coverage.

Fig. 1. The distribution of the socioeconomic deprivation status for all countries and territories considered for the analysis by World
Bank income level classification Conversely, in countries such as Haiti and Nigeria, less than one fifth of births among populations living in the poorest socioeconomic settings are attended by skilled professionals.In these countries, which have high urbanization rates and low education levels for women, people with low socioeconomic status may often live in precarious circumstances, including informal settlements. 19,20Financial limitations, barriers to accessing health facilities, and a lack of infrastructure to accommodate the growing population in cities often lead to births occurring without a skilled attendant. 21,22In addition, the rural populations in these countries, which are disproportionately socioeconomically disadvantaged, frequently experience barriers to accessing health care and long distances to facilities. 6,8,23n the other hand, countries such as Iraq, Malawi and Sao Tome and Principe have managed to achieve high coverage of skilled attendants at delivery across the population.Malawi, for example, released policy guidelines in 2007 which promote skilled attendants at delivery, and prohibit traditional birth attendants from performing routine deliveries. 24e also found wide gaps between the socioeconomically deprived group and the less deprived group for women who received antenatal care in at least four visits, and demand for family planning satisfied with modern methods.6][27] Unlike the almost universal access to skilled attendants at delivery among socioeconomically advantaged groups, improvement of coverage in the other two indicators is necessary across all socioeconomic deprivation status groups in the majority of the countries studied.Hence, efforts to reduce inequalities must be planned alongside actions to improve coverage for the entire population.Commitments to boost geographical accessibility, promote women's education, and implement policies attentive to the needs and desires of the underserved groups are key to advance both these indicators towards universal health coverage (UHC). 28,29he inequality patterns we observed, especially for women who received antenatal care in at least four visits and the presence of skilled attendants at delivery, are aligned with what would be expected according to the inverse equity hypothesis, 13 that is, when coverage is low, top inequality patterns emerge, and when coverage increases the pattern changes to bottom inequality.Given that median coverage is above 50% for all indicators, linear and bottom inequality patterns are more pronounced in most countries.Equity-oriented policies are necessary to increase coverage in the socioeconomically disadvantaged population, particularly for indicators with greater coverage gaps between groups.
The use of the socioeconomic deprivation status is not without its limitations.First, household surveys may not sample some of the most vulnerable populations, for example, those who are internally displaced or affected by disasters and conflicts.Second, cross-country comparisons are affected by the year of the survey due to the variations in survey periodicity, which also influenced the selection of countries for our analysis.Finally, as an absolute measure, the socioeconomic deprivation status leverages on its fixed cut-offs and clear definition contributing to a more consistent and comparable assessment of socioeconomic inequalities across settings.However, its usefulness is limited in countries with very low levels of thus-defined socioeconomic deprivation, as observed especially among upper-middle-income countries.This limitation is because the socioeconomic deprivation status' design is based on the UN's global Multidimensional Poverty Index, which intends to measure acute poverty. 8Future research may explore an extension to the original socioeconomic deprivation status cut-offs along the lines of a moderate poverty measure, which could be more relevant for higher-income countries and other countries progressing to reduce levels of socioeconomic deprivation. 30ur study shows that the socioeconomic deprivation status, as a composite index of absolute socioeconomic deprivation, is suitable to monitor health inequalities through national household survey data. 6This composite index can differentiate between groups of households in unfavourable conditions in most low-and middle-income countries.Unlike previous indices focused on reproductive, maternal and child health inequalities, this measure provides a comprehensive baseline for policy analysis and improves our ability to track progress towards the SDGs.Since the composite index captures absolute disadvantage, it facilitates comparisons across various disaggregated levels and different geographic areas, such as subnational regions, provided that adequate sample sizes are available.Furthermore, the composite index's comparability over time enables the evaluation of the long-term impacts of equity-focused policies.For countries conducting consecutive health surveys, this composite index can become a valuable tool to monitor and analyse trends in health coverage disparities.
In conclusion, the study revealed major gaps in three reproductive and maternal health indicators mostly fa-vouring the socioeconomically advantaged.Addressing these inequalities, as well as increasing coverage in many countries, is key to meeting the SDGs, in particular, targets related to UHC and preventing maternal and child mortality, as well as achieving the 2030 sustainable development agenda of leaving no one behind. 1

Fig. 2 .
Fig. 2. Distribution of reproductive and maternal health indicators by socioeconomic deprivation status, 48 low-and middle-income countries

Fig. 3 .%
Fig. 3. Coverage of demand for family planning satisfied with modern methods by socioeconomic deprivation status, 46 low-and middle-income countries

Table 3 . Description of the surveys included in the analysis of socioeconomic deprivation status, 2015-2019 Country or territory Survey year Source Sufficient sample size for analysis a Income group b
Bull World Health Organ 2024;102: 105-116 | doi: http://dx.doi.org/10.2471/BLT.23.290866 We used the World Bank country income level classification15 for the year the survey was conducted.Inequalities in health indicators by socioeconomic deprivation status Leonardo Z Ferreira et al.
DHS: Demographic and Health Survey; ENDES: Encuesta Demográfica y de Salud Familiar; MICS: Multiple Indicator Cluster Survey.a We did not conduct coverage analyses for a survey if the sample size for any of the three socioeconomic deprivation status measures was less than 25 households.b Bull World Health Organ 2024;102: 105-116 | doi: http://dx.doi.org/10.2471/BLT.23.290866

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Inequalities in health indicators by socioeconomic deprivation statusLeonardo Z Ferreira et al.